Leaning wheeled personal electric vehicle

ABSTRACT

An electric vehicle which is able to be steered by conventional bicycle-style steering, leaning rear steering or a combination of the two is herein described.

RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional PatentApplication Ser. No. 61/038,362, filed Mar. 20, 2008, entitled “LeanSteering Truck With A Torsion Spring Assembly” and claims the benefit ofU.S. Provisional Patent Application Ser. No. 61/038,364, filed Mar. 20,2008, entitled “Leaning Three Wheeled Personal Electric Vehicle”, whichare hereby incorporated by reference in their entirety.

FIELD OF THE INVENTION

This invention relates to wheeled leaning vehicles used primarily forpersonal transportation. The preferred embodiment described below fallswithin the emerging class of very light electric vehicles, a sub-classof electric vehicles used primarily for human transportation.

BACKGROUND OF THE INVENTION

This invention relates to electrically propelled leaning vehicles.Within the set of prior art the following subsets are known:

Within the subset of electrically propelled vehicles are a variety ofdesigns such as U.S. Pat. No. 5,918,692 which typically seek to minimizeweight and maximize interior volume thereby resulting in centers of masshigher than their gas powered counterparts. The limitations of thissub-set of the prior art include significantly degraded vehiclehandling, decreased corner entrance and exit speeds, greater passengerdiscomfort, and reduced traction in inclement environmental conditionssuch as rain or snow.

Within the subset of leaning vehicles a significant proportion envisioncomplicated, inefficient drive systems which seek to transfer the outputof a central power unit, such as a gasoline fueled engine, to aplurality of wheels. An examples of this includes U.S. Pat. No.4,456,277. This prior art is significantly limited by includingtelescoping drive shafts, chain-tensioner systems, or other methods todeliver power to wheels that have a variable distance, camber, and leanrelative to the power unit.

Within the subset of three-wheeled vehicles the prior art consists ofdesigns which often have a leading or trailing single wheel opposite apair of wheels. This subset is severely limited by the manner in whichthe two co-axial wheels are connected. Most limited are those whichfeature a solid axle interconnecting the two co-axial wheels, such asU.S. Pat. No. 3,776,353. These suffer from extremely poor cornering andhandling. The prior art also includes a set of designs whichinterconnect the pair of co-axial wheels using mechanical orelectro-mechanical linkages, such as U.S. Pat. No. 4,087,106. Thissub-set typically lacks provision to return the vehicle, and thereby therider, to a neutral position subsequent to cornering, turning, or otherhandling maneuvers.

The herein described invention overcomes the significant limitations ofthe prior art:

SUMMARY OF THE INVENTION

By combining one or a plurality of in-hub electrically powered motorswith the novel leaning mechanism described herein, a vehicle capable ofleaning into curves and handling in direct response to rider weightshifts is achieved. In one embodiment the powered wheel is located infront of the standing rider, with two turning, canting wheels placedbehind the rider. The rider is able to use handlebar controlled steeringduring slow-speed maneuvering and is able to tilt the riding platform,by shifting pressure to one foot or the other, to add in a variable andinstantaneous amount of rear-steering. In another embodiment one to fourin-hub electrical motors are employed, up to one on each of four wheels,two afore and two behind the seated or standing rider. The novel leaningmechanism described is placed both afore and behind the rider and eachinterconnects the two associated, powered wheels. In this embodiment anall wheel drive, lean steering, electric vehicle is established.

In one aspect a lean steering vehicle includes a main platform and afront wheel assembly coupled to a forward end of the main platform. Atorsion hanger assembly is coupled to the main platform, is rotatablearound a first axis, and provides resistive force against rotationaround the first axis from a neutral position. A first swing arm isrotatably coupled to the torsion hangar assembly. A first rear wheel isrotatably coupled to the first swing arm at a point distal to the pointat which the first swing arm is coupled to the torsion hangar assembly.An electric motor is coupled to at least one of the front wheel assemblyand the rear wheel to provide a driving force. Additionally a secondrear wheel can be included and coupled to the vehicle in the same manneras the first rear wheel.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an external side view of a preferred embodiment of thepresently disclosed vehicle.

FIG. 2 is a cross sectional side view of the vehicle

FIG. 3 is an external rear view showing the vehicle in a corneringconfiguration

FIG. 4 is a partial cross sectional top view of the leaning mechanismwhich interconnects a pair of wheels

FIG. 5 is a schematic showing vehicle geometries

FIG. 6 is an electrical block diagram of the vehicle power circuit

FIG. 7 is an alternative configuration of the presently describedinvention shown as a pair of leaning mechanisms

DETAILED DESCRIPTION OF THE DRAWINGS/DESCRIPTION OF A PREFERREDEMBODIMENT

The following detailed description is directed to certain specificembodiments of the invention. However, the invention can be embodied ina multitude of different systems and methods. In this description,reference is made to the drawings wherein like parts are designated withlike numerals throughout.

As shown in FIG. 1 a preferred embodiment of the herein describedvehicle includes a front wheel assembly 101 comprised of a tire 102 andhub 103 or other support structure which contains a motor concentric tothe front axle 104. This axle 104 connects the handlebars 105 andsteering column or columns 106 to the wheel assembly 101. In thisembodiment the rider stands atop the main platform 107. In anotherenvisioned embodiment the rider is seated on a structure rigidly mountedor suspended from either the main platform 107 or the rear platform 108.In the presently shown embodiment the rear platform 108 serves toprotect the rider from the rear wheel assembly 120 while providing amounting location for a seat, storage, display, engine to supporthybrid-electric operation, or other accessories. Pivotally mounted andinterconnecting the front wheel assembly 101 to the rear wheel assembly120 is a supporting frame 110. In another envisioned embodiment amonocoque design supports the rider via the main platform 107 andinterconnects the pivotally mounted front wheel assembly 101 and therear wheel assembly 120. It is envisioned that any of a variety ofcommonly known suspensions systems, such as coil-over spring-dampersystems can be combined with the rear wheel assembly 120, with the frontwheel assembly 101, or both.

In this presently described embodiment the rear wheel assembly 120 iscomprised of a pair of swing arms 121 which span the distance betweenthe torsion hanger assembly 122 and the rear wheels 123. Each rear wheel123 is mounted to a swing arm 121 so as to provide free rotation, inthis embodiment through the use of sealed bearings. The swing arms 121also directly support brake calipers 124 which transfer force onto rearbrake rotors 125, which are concentrically mounted to the freelyrotating rear wheels 123, in order to stop the rotation of the said rearwheels 123.

As shown in FIG. 2 the afore described vehicle is presented in crosssection. Batteries 201 are housed within the frame 110 and connectedelectrically to the controller device 210 and thereby the front in-hubmotor 103. In an illustrative embodiment the front in-hub electricalmotor is of a power rating ranging from 250 Watts to 2500 Watts and thebatteries are an assembly of cells totaling 12 to 96 Volts. Activationof this circuit occurs by manipulation of the handlebar 105 mountedthrottle 202 and results in forward motion of the vehicle. The torsionhanger assembly 122 houses a torsion spring 230 and rotates freely abouta vertical axis of rotation. The torsion hanger assembly 122 and torsionspring 230 are limited in other axes and planes of motion by a top plate231 and a bottom torsion hanger base 232 which is rigidly mounted to theframe 110. Sealed top 233 and bottom 234 bearings allow free rotationabout the axis of rotation while a pivot bolt 235 interconnects the topplate 231 and bottom torsion hanger base 232. In this manner, leaning ofthe main platform 107 results in the compression of the torsion spring230 (or other spring force source such as an elastic polymer element)and a combined, proportional tilt and rotation of both rear wheels 123.A decrease in the amount of lean of the main platform 107, for exampleby the rider changing downward pressure on a point not located on thelongitudinal axis of the main platform 107, results in the spring force(though the force can be provided by a source other than a spring)overcoming this pressure exerted on the main platform 107 and therebycauses the vehicle to return to its neutral, in this instance uprightposition. In one embodiment the torsion hangar assembly is as describedin U.S. patent application Ser. No. 12/406,829, titled Lean SteeringTruck With A Torsion Spring Assembly, filed Mar. 18, 2009, herebyincorporated by reference.

As shown in FIG. 3 the previously described vehicle is shown in aleaning configuration. The rider (not shown) is normal to the mainplatform 107 and nominally parallel to the steering column 106. The rearwheels 123 rotate, as a set, about the central, vertical, axis ofrotation which is coaxial to the pivot bolt 235. A control arm 310connects each swing arm 121 to the torsion hanger base 232. Thesecontrol arms 310 limit the motion of the swing arms 121 and create alinear and inverse relationship between the lean of the main platform107 and the rotation of the rear wheel assembly 120. In the preferredembodiment the control arms 310 are connected to the torsion hanger base232 and to the swing arms 121 using a ball or Heim joints 311. When, asin envisioned herein, these control arms 310 are placed in parallel to,and directly below, the longitudinal axis of the swing arms 121 stresseson the assembly 120 are minimized. As the main platform 107 is leaned areactionary ground force acts upon the inside rear wheel and thereby theinside swing arm 121 and inside control arm 310 such that the torsionspring is compressed. The restorative spring force counteracts thissequence of events causing the main platform 107 and thereby the riderto return to a neutral position.

As shown in FIG. 4 the leaning mechanism is shown in top view, partialcross section. The swing arms 121 are connected to the torsion hangerhousing 410 by way of swing arm bolts 411. Sealed bearings 412 allow thefree rotation of the swing arms 121 about an axis of rotation defined bythe longitudinal axis of the swing arm bolts 411. Control arms 310spherically rotationally join the swing arms 121 to the torsion hangerbase 232. The torsion hanger housing 410 is allowed to rotate about anaxis of rotation normal to the primary axis of the vehicle platform 110and defined by the longitudinal axis of the pivot bolt 235. The torsionspring 230 is secured by way of spring guides 420 and spring stops 421,or alternatively an enclosing spring chamber, which are adjustable byway of a plurality of set screws 422. Manipulating the set screws 422results in increased or decrease compression of the torsion spring 230.A change in compression has a direct and necessary impact on the ridedynamic and in particular the amount of force exerted by the torsionspring 230 in order to return the vehicle to an upright position. Areduction in spring force results in a more complaint vehicle that lessforcefully returns to an upright position. Conversely an increase inspring force results in a vehicle that more forcefully returns to anupright, neutral position. The torsion spring 230 housed within thespring chamber 430 is compressed prior to assembly of the rear wheelassembly 120 so as to provide a riding situation in which the torsionspring 230 is continuously in compression. The swing arms 121 directlyand rigidly house the brake calipers 124 thereby eliminating additionalhardware or mechanical connections and reducing the overall weight ofthe swing arms 121. On the external surface of the torsion hangerhousing 410 are two mechanical protrusions, in this embodiment threadedblots 430, serving to limit the range of free rotation about the pivotbolt 235 and thereby the extent to which the main platform 107 and thevehicle frame 110 is allowed to lean relative to the road surface.

In one embodiment the torsion spring 230 and spring chamber 430 form aninterchangeable sub-assembly which, when changed to a torsion spring 230of varying spring constants so vary the ride dynamics of the vehicle. Inanother embodiment the torsion spring 230 is of a progressively varyingspring constant; for every degree the torsion spring 230 is compressedan incrementally varying force is exerted upon the assembly 120 therebyproviding varying ride dynamics in relation to the lean angel of themain platform 107.

As shown in FIG. 5 the front wheel assembly 101 is connected to thesteering column 106 by way of the front axle 104. This distance from thereal location of the axle 104 to the closest point along thelongitudinal axis of the steering column 106 is described by the offset510. In a preferred embodiment this offset is between 0 and 6 inches.Where radius 501 of the front wheel assembly 101 normally intersects theground plane 502 is the point 503. Another point 504 is located wherethe longitudinal axis of the steering column 106 intersects the groundplane 502. The distance between points 503 and 504 is the trail distance520. In a preferred embodiment the trail distance 520 is between 0 and 3inches. Where the rear wheel 123 radius 505 normally intersects theground plane 502 is the point 506. The distance between point 503 andpoint 506 is the wheelbase 530. In a preferred embodiment the wheelbaseis between 40 and 120 inches. The careful calculation of theaforementioned geometries results in a natural, balanced ridingexperience and is governed by Proportionality 1:

-   -   Lean to Turn Ratio∝{Rider Weight, Vehicle Weight, Torsion Spring        Constant, Swing Arm Lengths, Front Wheel Offset, Front Wheel        Trail, Wheel Base, Front and Rear Wheel Radii}

And the Restorative force exerted upon the vehicle and rider is governedby Proportionality 2:

-   -   Restorative Force∝{Normal Force, Length of Swing Arms, Wheel        Radii, Inflated Tire Spring Constant, Torsion Spring Constant,        Combined Rider and Vehicle Weight, and Wheel Base}

As shown in FIG. 6 electrical energy is stored in batteries 601. Thebatteries 601 are connected to the controller 602 by electric wires.Given input from the handlebar 105 mounted throttle 603, power isproportioned and transmitted to the in-hub electrical motor 604. Thecontroller 602 also proportions and powers accessories including lights605, and audible horn 606, and a display showing battery charge level607. Actuation of either one of two brake levers 608 results in a cutoffsignal being sent to the controller 602. In the case of decelerationwith no input from the throttle kinetic energy is transformed intoelectrical energy by the motor 604 and transferred into the batteries601 by way of the controller 602.

In an alternative embodiment the controller 602 includes a secondary allwheel drive controller 610 to regulate power distribution and monitorpower distribution to each of Left Front Motor 611, Right Front Motor612, Left Rear Motor 613, Right Rear Motor 614. In this manner an allwheel drive configuration is achieved together with a sensing system tomonitor and counteract wheel slippage and respond directly to varyingwheel speeds, as in cornering.

As shown in FIG. 7 a pair of rear wheel assemblies 120 can be used. Aspreviously described, the rear wheel assembly 120 is place behind thestanding or seated rider and attached rigidly to the frame 110. In thisalternative configuration a second rear wheel assembly 120 is attachedafore the rider and also rigidly attached to the frame. The result is afour wheel leaning vehicle. Power is provided as previously described toin-hub electric motors located at either the front 710, 711 wheels orthe rear wheels 720, 721. Intelligent All Wheel Drive is alsoenvisioned, also as previously described, wherein the in-hub electricmotors are located on all four wheels 710, 711, 720, 721.

The above description of the disclosed embodiments is provided to enableany person skilled in the art to make or use the invention. Variousmodifications to these embodiments will be readily apparent to thoseskilled in the art, and the generic principles described herein can beapplied to other embodiments without departing from the spirit or scopeof the invention. Thus, it is to be understood that the description anddrawings presented herein represent exemplary embodiments of theinvention and are therefore representative of the subject matter whichis broadly contemplated by the present invention. It is furtherunderstood that the scope of the present invention fully encompassesother embodiments and that the scope of the present invention isaccordingly limited by nothing other than the appended claims.

1. A lean steering vehicle comprising: a main platform; a front wheelassembly coupled to a forward end of the main platform; a torsion hangerassembly coupled to the main platform, rotatable around a first axis,and providing resistive force against rotation around the first axisfrom a neutral position; a first swing arm rotatably coupled to thetorsion hangar assembly; a first rear wheel rotatably coupled to thefirst swing arm at a point distal to the point at which the first swingarm is coupled to the torsion hangar assembly; and an electric motorcoupled to at least one of the front wheel assembly and the rear wheelto providing a driving force.
 2. The vehicle of claim 1 furthercomprising a first control arm coupled at a first end to the first swingarm at a location on the first swing arm distal to point at which thefirst swing arm is coupled to the torsion hangar assembly and coupled ata second end to a part of the vehicle that is fixed in relationship tothe main platform.
 3. The vehicle of claim 2 further comprising a handlebar coupled to a steering column with the steering column being coupledto the front wheel assembly.
 4. The vehicle of claim 2 furthercomprising a second swing arm rotatably coupled to the torsion hangarassembly; a second rear wheel rotatably coupled to the second swing armat a point distal to the point at which the second swing arm is coupledto the torsion hangar assembly; and a second control arm coupled at afirst end to the second swing arm at a location on the second swing armdistal to point at which the second swing arm is coupled to the torsionhangar assembly and coupled at a second end to a part of the vehiclethat is fixed in relationship to the main platform.
 5. The vehicle ofclaim 1 wherein the torsion hangar assembly includes a torsion spring.